This invention relates to a flushing system for an outboard motor and more particularly to an improved and simplified arrangement for flushing the cooling jacket of an outboard motor.
As is well known, most outboard motors have liquid cooling systems that operate by drawing water from the body of water in which the associated watercraft is operated, circulating it through the cooling jacket of the engine, and returning the water back to the body of water once the engine has been cooled. This obviously results in a wide variety of water conditions that pass through the engine cooling jacket. Therefore, it has been practice for the operators to flush the cooling system of the engine from time to time. This is particularly desirable when the outboard motor has been operating in a marine (salt water) environment.
Many types of "flushing cuffs" have been provided. These are devices that attach around the water inlet portion of the outer housing which is normally located in the lower unit. These cuffs have a fitting to which a hose can be attached, and thus city water can be employed for flushing the outboard motor. Obviously, these devices are not particularly convenient and they normally require removal of the outboard motor from the watercraft or removal of the watercraft with the attached outboard motor from the body of water.
Another type of device has been proposed wherein the outboard motor is provided with a fitting that is connected to the cooling circuit and to which a hose may be attached. Frequently, this fitting also serves as the tell-tale for the cooling system, and such an arrangement is shown in FIG. 1.
Referring specifically to FIG. 1, an outboard motor is identified generally by the reference numeral 11 and is comprised of a power head, indicated by the reference numeral 12, which is comprised of a powering, water-cooled internal combustion engine 13 and a surrounding protective cowling comprised of a lower tray portion 14 and a detachably connected main cowling portion 15.
Various types of internal combustion engines may be employed, and these engines are frequently provided with internal cooling jackets, indicated by the reference numeral 16 and shown in phantom. Since the construction of the engine 13 per se and its cooling jacket 16 forms no part of the invention, the construction of the prior art engines and cooling jackets and that of the invention will not be described further.
The engine 13, as is typical with outboard motor practice, is supported so that its output shaft rotates about a vertically extending axis. This output shaft is coupled to a drive shaft (not shown) that depends into a drive shaft housing 17 which depends from the power head 12. This drive shaft housing terminates in a lower unit 18 where the drive shaft is coupled to a forward/neutral/reverse transmission (not shown) so as to drive a propulsion device such as a propeller, which also is not illustrated in this figure.
A coolant pump 19 is disposed at the interface between the drive shaft housing 17 and the lower unit 18. This coolant pump 19 is driven by the drive shaft in a manner well known. The coolant pump 19 draws water from the body of water in which the outboard motor 11 is operating, through a water inlet opening 21 formed in the lower unit 18. This water is then delivered to the engine cooling jacket 16 through an internal conduit 22 that extends upwardly through the drive shaft housing 18.
After the water has circulated through the engine cooling jacket 16, it is dumped into a return conduit 23. The conduit 23 discharges into the exhaust system which is normally contained within the drive shaft housing 17 for discharge of the water along with the exhaust gases through an underwater exhaust gas discharge, indicated at 24. This discharge 24 may comprise a through-the-hub propeller discharge.
In addition, there is provided a small above-the-water discharge 25 through which a portion of the cooling water is normally discharged so as to provide a visual indication to the operator (tell-tale) that coolant is being circulated through the engine cooling jacket.
In accordance with one type of prior art device, a Valve assembly 26 is provided at the discharge end of the tell-tale 25 and which permits a small amount of water flow under all conditions. This may also include, in addition to a check-type valve, a manual valve that may be manually closed to a restricted position and opened to a full-flow position.
In this open full-flow position, a male fitting 27 of a garden hose 28 may be threaded so that water may be flushed through the cooling system. Because this flushing attachment is at the rear of the outboard motor, it is difficult to utilize when the outboard motor is attached to a transom of a watercraft, as shown partially and in cross section at 29. In addition, the flow of flushing water is opposite to that of the normal flow path, and it may be desirable or necessary to plug or otherwise close the underwater exhaust gas discharge 24 to ensure that the flow will pass through the cooling jacket 16 and not merely be discharged through the discharge opening 24 without ever flushing the cooling jacket 16.
From this description it should be readily apparent that this type of prior art construction, although it has some advantages over the cuff-type flushing system, does have some areas that can be improved upon. For example, the type of valve arrangement that must be employed requires not only manual operation, but also requires the provision of a check-type valve, which adds to the cost of the assembly. Furthermore, these systems may also be prone to leakage. Furthermore, and as has been noted, the attachment of the hose for flushing purposes is difficult, particularly when the watercraft still is in the body of water.
It is, therefore, a principal object of this invention to provide an improved flushing system for an outboard motor.
It is a further object of this invention to provide a flushing system for an outboard motor that offers flexibility in attachment of the flushing hose to the system and which permits flushing even when the watercraft remains in the body of water.
It is a further object of this invention to provide an improved flushing system for an outboard motor that does not require a valve for its operation.
Referring again to FIG. 1, the additional conventional components of the outboard motor 11 will be described, as this description will also be used in lieu of a detailed description of these conventional components in conjunction with the invention.
A steering shaft (not shown) is connected in a suitable manner to the drive shaft housing 18. This steering shaft is journalled within a swivel bracket 31 for steering of the outboard motor 11 about the steering axis defined by the swivel bracket 31. The swivel bracket 31 is, in turn, coupled by a horizontal tilt pin 32 to a clamping bracket 33 that is affixed to the watercraft transom 29 in a known manner. The pivot pin 32 permits tilt and trim movement of the outboard motor 11, as is well known in this art.